BOTULINUM TOXIN IN CERVICAL DYSTONIA - LOW-DOSAGE WITH ELECTROMYOGRAPHIC GUIDANCE

Sixty patients with idiopathic cervical dystonia were treated a total of 240 times with botulinum toxin type A (BTA). Selected muscles were injected with BTA under electromyographic (EMG) guidance. The clinical effect was measured on the Tsui scale and a 10-point anchored visual analogue scale. A dosage of 150-300 mouse units was used in 77% of the treatments (mean 204 mouse units). Based on the Tsui scale, 45% of 24 0 treatments were still effective at the moment of reinjection (median improvement 2 points). Based on the 10-point anchored visual analogue scale, 73% of treatments were successful (median improvement 3 points ). Forty-eight patients (80%) responded favourably to the treatment. S ide-effects were mild and transient. Dysphagia occurred in 9% of treat ments. Antibody production was investigated in 41 patients and was neg ative in all. A striking difference from previous reports is the lower dosage used in this study. The clinical response, however, was simila r to that of other studies. We conclude that a dosage of 200-400 mouse units BTA (Dysport) may also be effective in the treatment of cervica l dystonia, but with fewer side effects. EMG guidance and application of BTA into deep cervical muscles may further improve the clinical eff ect.